ICP 24V Transformer for ZAMA004AHA3 — SPST 40VA Control | Ships Today

Overview

This OEM 24V control transformer (ICP part #1057251) supplies the low-voltage power that runs the thermostat, relays, and control circuits in your air handler or furnace. Rated at 40VA, it steps line voltage down to a stable 24V for the SPST control loop. A failed transformer takes the entire 24V circuit offline: the thermostat goes dark, relays and contactors will not pull in, and the system will not start. Typical causes include a shorted secondary, an overloaded control circuit, or heat damage from voltage spikes.

Specifications

Compatibility

Direct-fit replacement for ICP, Tempstar, Heil, and Comfortmaker equipment using the 1057251 control transformer, including model ZAMA004AHA3. Verify primary voltage and VA rating against the original part before installing.

Installation Guide

1. Safety First — Disconnect power and verify zero voltage with a multimeter.
2. Access — Remove the control-box/service panel to reach the transformer.
3. Document — Photograph primary and secondary wiring before disconnecting.
4. Remove — Disconnect the leads, unbolt the transformer from its bracket, and remove it.
5. Install — Mount the new transformer and reconnect primary and secondary leads per your photo.
6. Test — Restore power and confirm 24V across the secondary and normal control operation.

Signs You Need a Replacement

• Blank thermostat or no 24V at the control board
• Relays and contactors fail to energize
• Low-voltage fuse blows repeatedly
• Transformer is hot, buzzing, or scorched

Shipping & Returns

Ships same day before 3 PM CST. 30-day returns. Backed by the National HVAC Parts fitment guarantee.